Methods for assigning provider devices as designated forwarders for different vlans

Abstract

A method of forwarding traffic to a client edge (CE) device comprises using an ordered list of virtual local area network (VLAN) identifiers, where each VLAN identifier corresponds to a respective one of a plurality of VLANs, to assign, for each of the plurality of VLANs, one of a plurality of provider edge (PE) devices that are connected to the CE device to forward traffic that is within a class of traffic to the CE device.

1 . A method for a first provider edge (PE) device to determine if it will act as a designated forwarder (DF) for each of a plurality of virtual local area networks (VLANs), the method comprising:
 receiving, at the first PE device, a plurality of VLAN identifiers, each VLAN identifier identifying a respective one of the plurality of VLANs;   generating an ordered list of the VLAN identifiers; and   determining, for each VLAN, whether the first PE device is to act as the DF for forwarding traffic of the VLAN that is within a certain class of traffic to a customer edge (CE) device, where the CE device is connected to a plurality of PE devices that includes the first PE device, and the determining is based on a position of each VLAN identifier within the ordered list and based on a number of PE devices in the plurality of PE devices.   
     
     
         2 . The method of  claim 1 , the method further comprising generating an ordered list of the PE devices in the plurality of PE devices. 
     
     
         3 . The method of  claim 2 , wherein the determining is further based on the position of the first PE device in the ordered list of the PE devices in the plurality of PE devices. 
     
     
         4 . The method of  claim 1 , wherein the certain class of traffic includes at least one of broadcast traffic, unknown unicast traffic and multicast traffic (BUM traffic). 
     
     
         5 . The method of  claim 1 , wherein the class of traffic includes all three of broadcast traffic, unknown unicast traffic and multicast traffic (BUM traffic). 
     
     
         6 . The method of  claim 5 , wherein the BUM traffic is received at each PE device in the plurality of PE devices. 
     
     
         7 . The method of  claim 1 , wherein each of the plurality of VLANs is associated with an Ethernet Virtual Private Network (EVPN) instance. 
     
     
         8 . A method for a first provider edge (PE) device that is already acting as a designated forwarder (DF) of broadcast traffic, unknown unicast traffic and multicast traffic (BUM traffic) for at least one virtual local area network (VLAN) to a customer edge (CE) device to determine if it will act as a DF for one or more additional VLANs to the CE device, where the CE device is connected to a plurality of PE devices that includes the first PE device, the method comprising:
 determining if the first PE device, when acting as a selected one of the plurality of PE devices, satisfies a first rule, where the first rule is satisfied if a number of the plurality of VLANs for which the selected one of the plurality of PE devices is presently assigned as the DF is equal to or less than a number of the plurality of VLANs for which the selected one of the plurality of PE devices is not acting as DF;   determining if the first PE device, when acting as the selected one of the plurality of PE devices, satisfies a second rule, where the second rule is satisfied if the number of the plurality of VLANs for which the selected one of the plurality of PE devices is acting as DF for is equal to or less than a half of the total number of VLANs in the plurality of VLANs; and   determining if the first PE device is the lowest PE device in an ordinal list of the plurality of PE devices that satisfies both the first rule and the second rule.   
     
     
         9 . The method of  claim 8 , the method further comprising assigning the first PE device as the DF of BUM traffic for the VLAN corresponding to a first VLAN identifier in an ordered list of VLAN identifiers in response to determining that the first PE device is the lowest PE device in an ordinal list of the plurality of PE devices that satisfies both the first rule and the second rule. 
     
     
         10 . A method of forwarding traffic to a client edge (CE) device, the method comprising:
 using an ordered list of virtual local area network (VLAN) identifiers, where each VLAN identifier corresponds to a respective one of a plurality of VLANs, to assign, for each of the plurality of VLANs, one of a plurality of provider edge (PE) devices that are connected to the CE device to forward traffic that is within a class of traffic to the CE device.   
     
     
         11 . The method of  claim 10 , wherein the class of traffic includes at least one of broadcast traffic, unknown unicast traffic and multicast traffic. 
     
     
         12 . The method of  claim 10 , wherein the class of traffic includes all three of broadcast traffic, unknown unicast traffic and multicast traffic. 
     
     
         13 . The method of  claim 10 , wherein the traffic in the class of traffic is received at each of the PE devices that are connected to the CE device. 
     
     
         14 . The method of  claim 10 , wherein each of the plurality of PE devices determines whether it is assigned to forward the class of traffic to the CE device for each of the plurality of VLANs. 
     
     
         15 . The method of  claim 10 , further comprising generating an ordered list of the plurality of PE devices, and using the ordered list of plurality of PE devices in assigning, for each of the plurality of VLANs, one of the plurality of PE devices to forward a class of traffic to the CE device. 
     
     
         16 . The method of  claim 10 , wherein each of the plurality of VLANs is associated with an Ethernet Virtual Private Network (EVPN) instance.